Effect of modulating thrombomodulin expression on renal injury in rats with diabetic nephropathy

Abstract

Objective To investigate the effect of modulating thrombomodulin (TM) expression on renal injury in a rat model of diabetic nephropathy (DN) and explore the possible mechanism. Methods We examined the expression of liver X receptor-α (LXR-α), TM, coagulation factor XⅢ-A (FXⅢ-A) and CD163 in 25 renal biopsy samples from patients with DN and in 6 normal renal tissue specimens using immunohistochemistry. Twenty-four 12-week-old male db/db mice with DN were randomly assigned into 4 equal groups and treated daily with intragastric administration of normal saline or LXR-α agonist T0901317, or with intravenous injection of an adenoviral vector carrying TM shRNA or the control adenoviral vector for 7 consecutive days; 6 wild-type C57BL6 mice with intragastric saline treatment served as the normal control group. Four weeks after the treatment, the expression of TM, LXR-α, FXⅢ-A and CD163 in the renal tissues of the mice were detected using Western blotting, the levels of tumor necrosis factor-α (TNF-α) and interleukine-6 (IL-6) were detected by ELISA, and the urinary microalbumin level was determined. Results The renal expression levels of TM and LXR-α were decreased (P < 0.05) and those of FXⅢ-A and CD163 were increased significantly (P < 0.05) in the kidney tissues of DN patients compared with normal kidney tissues. In db/db mouse model of DN, the expression levels of TM and LXR-α were positively correlated while those of FXⅢ-A and CD163 were negatively correlated with glomerular filtration rate (P < 0.05). Compared with the wild-type mice, the mouse model of DN showed significantly increased urinary microalbumin levels and serum levels of TNF-α and IL-6, lowered renal expressions of TM and LXR-α, and increased renal expression of FXⅢ-A and CD163; these changes were further exacerbated in the mice treated with Ad-TM shRNA (P < 0.05) but significantly improved in the mouse models treated with T0901317. Conclusion Upregulating TM expression can reduce urinary microalbumin level in db/db mouse model of DN by inhibiting the renal expression of FXⅢ-A and CD163 and downregulating blood levels of inflammatory mediators.

Keywords

• thrombomodulin
• diabetic nephropathy
• liver x receptor-α
• coagulation factor xⅲ-a
• db/db mice